1. Field of the Invention
The invention relates to a semiconductor and a method of fabricating the same.
2. Description of Related Art
A transistor is a solid state semiconductor device advantageous in small size, high efficiency, long lifetime and high speed. In recent years, with advancement in technologies, the transistor is now capable of enduring high voltage and high power, and becoming an important role in a high power device.
A bipolar junction transistor (BJT) refers to a transistor composed of two PN junctions formed by utilizing three different doped regions. The BJT is a device having three terminals including an emitter (E), a base (B) and a collector (C). The BJT is capable of amplifying signals, and providing more preferable power control, high speed operation and endurance capacity. Thus, the BJT is widely used by circuits with current control requirements in fields including a switch device controlling a DC power load, an analog signal amplifier, a 3D bipolar simulation, a NPN element, and an AC frequency response. The BJT is also an important device in an ultra high speed discrete logic circuit including applications such as an emitter coupled logic (ECL), a power switching device, and a microwave power amplifier. How to amplify the signal, reduce noises while maintaining a high breakdown voltage is one of the issues to be solved in applications of amplifiers.